[hpsdr] It lives - but....

[Mike Stevenson]

?I had problems with amplified speakers and my headphones when running 400 
watts into the antenna.
I solved this with  better chokes on the antenna co-ax, both ends using type 
31 material and always running the audio output at a high level setting. 
This means that I have to use an external audio attenuator with the 
headphones as they are too sensitive.

Hope to work you soon on 80m.

Mike G8ALS

----- Original Message ----- 
From: "Paul Fletcher" <paul_fletcher at me.com>
To: <hpsdr at lists.openhpsdr.org>
Sent: Wednesday, January 05, 2011 8:55 PM
Subject: [hpsdr] It lives - but....


> ***** High Performance Software Defined Radio Discussion List *****
>
> Got my HPSDR transceiver on air this evening with the 100W PA, all 
> generally fine with some good audio reports. However, I am getting RF 
> feedback in the headphones (not on the transmitted signal) and wondered if 
> anyone else has experienced this? I get nothing when using a dummy load 
> but get feedback when using a well matched antenna (and there is nothing 
> coming up the outside of the coax either - it's well choked and I've had a 
> clamp on RF ammeter on it as well).
>
> I'm thinking grounding issue (only think connected to Mercury is the 
> headphones and the coax).
>
> Suggestions welcome as always.
>
> Paul M1PAF
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